The goal of "closing the achievement gap" in education is often proclaimed and is emphasized in the "No Child Left Behind Act." What is meant by the achievement gap and how much progress has been made? A large body of literature examines the causes, conditions, and explanations for the achievement gap. Many educational organizations have focused on strategies to reduce the gap and encouraged the nation to learn from schools and districts that are succeeding. Researchers have worked to improve standardized tests and to lessen social and cultural bias, yet some commentators insist that many tests do not adequately measure the capabilities of all students, such as those for whom English is a second language. Research shows that strong parent involvement in high quality school and family partnerships can lead to substantial student achievement gains, regardless of family social and economic background. Research also shows that all students at a school benefit from parent involvement, not only those students whose parents volunteer at the school. Studies have found that parent participation appears pivotal: it is positively related to both parent satisfaction and student achievement. Substantial evidence exists to show that children whose parents are involved in their schooling have significantly increased academic achievement and cognitive development. In their review of existing research, the San Diego County Office of Education concluded that the most accurate predictor of a student's achievement in school is not income or social status, but the extent to which that student's family is able to: (1) Create a home environment that encourages learning; (2) Express high (but not unrealistic) expectations for their children's achievement and future careers; and (3) Become involved in their children's education at school and in the community. (Contains a list of 6 resources.) [This article was produced by the Center for Assessment and Evaluation of Student Learning (CAESL) at WestEd.]